Study On Mechanism And Prevention Technology For Slagging Of Biomass Pellet Fuel

Slagging not only reduces the the efficiency of combustion,but also improves the boiler's operating cost.In addition,under the effect of flue gas,the tube wall will be corroded by the ash which is bonded to the surface.This will increase the cost to maintain the equipment.The reasearch chose K₂CO₃,CaO,Al₂O₃,SiO₂ as additives adding into the straw fuels by different proportion.X-ray diffractometer?XRD?was used to analyse the composition of ash with different additives.It found that the fuel slagging include two kinds of ways:on one hand SiO₂ and silicate Can react with potassium and generate volatile alkali metal silicate.This will improve ash slagging speed directly.On the other hand a solid alkali metal sulfate and sour salt aerosol particles was softened in a high temperature,and forming a viscous surface.These sticky particles will be deposited to form slagging when suffering low temperature heating surface.K₂CO₃,CaO,Al₂O₃,SiO₂,Fe₂O₃,MgO was chose as additives with different proportion into the straw fuels and used ASTM methods to get the fuel ash,then through the ash melting tester to test the ash melting point.found that small content of K₂CO₃ could improve the ash melting point,but it would falling the ash melting point when it incresed a certain value.With the content of Al₂O₃,SiO₂,MgO added,ash melting point decreased firstly and increased then.six different additive mixed in different proportions joined in the fuel,its ash melting point was measured,The proportion of K₂CO₃,CaO,Al₂O₃,SiO₂,Fe₂O₃,MgO was chose as independent variable and the softening temperature as the dependent variable.Built the regression model.testing found that Fe₂O₃ was not efficiency.Straw ash sample forming was analysed in different conditions by using SEM,AFM and other equipment.The reasearch found that the content of Al₂O₃ and K₂CO₃ adding should be controlled under 1.5%,SiO₂ and CaO added more than 3% under the condition of 1200? would improve the tendency of slagging obviously.